In the midsts of having Nightmares about creatures from the sky coming to destroy the entire valley, Moon-Boy falls out of his tree and witnesses something crashing to earth. It crashes with such an impact it begins tearing the land apart so Devil Dinosaur and Moon-Boy leave to investigate the source.

They arrive at the crash sight and unbeknownst to them it is a space-craft, out from which come humanoid alien/robot creatures that Moon-Boy dubs sky demons. Who begin to lay waste to all life-forms, knocking out Devil and capturing Moon-Boy and taking him aboard there craft. While the robots begin destroying the valley, two of the Hill Folk tribe, White-Hair and Stone-Hand seek out Devil in hope of him aiding them.

Finding him after just recovering from his unconsciousness, the pair witness him taking out one of the "Sky Demons". But as Devil turns his back the sky demon is not fully dead and Stone-Hand saves his life from the aliens attack. The three then strike up a partnership, with the hill folk following Devil as there new leader. Returning to the craft, the trio witness the aliens taking both Dinosaurs and the Hill-Folk being taken aboard for study. When one tries to escape, he is instantly vaporized. Fearing for there lives Stone-Hand tries to leave but White-Hair insist they stay with Devil, who turns away from the craft and starts towards The Tower of Death, in a plan to overwhelm the invaders with what lies within.